Meteorological measurement arrangement

ABSTRACT

A meteorological measurement system is disclosed having a meteorological mast which extends upwards from a base and supports one or more wind gauges. At least one of the wind gauges is disposed in the region of the upper tip of the mast and is designed as a remote wind gauge for measuring wind conditions at one or more remote measurement locations situated above the mast tip at a distance from the remote wind gauge. At least another wind gauge is disposed in the region of the upper tip of the mast in close spatial proximity to the remote wind gauge and is designed as a local wind gauge for measuring wind characteristics at the location of the remote wind gauge.

The invention relates to a meteorological measurement arrangement havingat least one meteorological mast which extends from a substrate in anupward direction and which carries one or more wind measurement devices,the or at least one of the wind measurement devices being arranged inthe region of the upper mast tip and being constructed as a remote windmeasurement device, by means of which wind properties can be measured atone or more remote measurement locations which are located above andwith spacing from the remote wind measurement device.

A meteorological mast, by means of which the wind speed and the winddirection can be measured is known from EP 2 128 438 A2.

EP 2 080 901 A2 discloses a method for estimating the properties of thefreely flowing wind for a wind turbine which comprises a rotor, the windspeed being estimated at the pod of the wind turbine, at least oneangular position of the rotor for measuring the wind properties at thepod being determined from the estimated wind speed and the windproperties at the pod at the previously determined angular position ofthe rotor then being measured. A meteorological mast can thereby bedispensed with.

DE 10 2004 051 843 A1 discloses a wind turbine having a substructure, amachine housing which is arranged thereon and which can be adjusted inan azimuthal manner by means of a pivot device, a rotor which isrotatably arranged at an end face of the machine housing and whichdrives a generator for producing electrical energy, measurement devicesfor measuring wind speed and wind direction, and for anelectromechanical quantity, and a control for the pivot device. One ofthe transmitters is constructed as a cup anemometer and serves todetermine the wind strength. Another of the transmitters is constructedas a wind vane and serves to establish the wind direction. The controlwith the transmitters thereof for the wind speed and the wind directionmay be arranged on the machine housing of the wind turbine or on aseparate tower.

A meteorological mast is generally used to measure properties of thewind in accordance with the height above a substrate on which the maststands, the wind properties comprising, for example, the wind speed andthe wind direction. For example, wind properties supplied by ameteorological mast are used for the evaluation of the occurrence ofwind at a location in order to be able to assess whether this locationis suitable for the construction of a wind park. In addition to the windspeed and the wind direction, the wind properties preferably alsocomprise the vertical wind shear, measurements having shown that thevertical wind shear varies locally and temporally.

The nominal power of wind turbines has been increasing for some time andmay nowadays be in the range of several megawatt, wind turbines havingsuch a nominal power also being referred to as multi-megawatt turbines.As the nominal power increases, however, the height of the rotor hubalso increases so that the height of the meteorological masts would haveto increase in order to be able to establish the wind properties atleast at the height of the rotor hub. However, there are currentlyseveral reasons for limiting the height of meteorological masts, inparticular to a height of 60 m or less. A first reason is that, below amast height of 60 m, no permission is required from the US FederalAviation Administration (FAA) for the construction of masts. A secondreason is that the costs for meteorological masts significantly increasewhen the mast heights exceed 80 m or 100 m.

If a meteorological mast having a mast height of 60 m is used toevaluate the occurrence of wind at a height which exceeds 60 m, amathematical extrapolation of the wind properties supplied by the mastat this height is carried out. However, it is known that such anextrapolation is linked with errors.

Remote wind measurement devices for establishing a remote wind field areknown from the prior art. Such remote wind measurement devices are basedon the use of the Doppler effect, the frequency displacement betweenemitted waves and reflected waves being evaluated. Both electromagneticwaves and sound waves can be used. The remote wind measurement devicesare arranged at the height of the substrate and emit the waves which arecollimated to form a beam in an upward direction. Reflections of thewaves at inhomogeneities in the atmosphere lead to a back-scatteredsignal with the Doppler frequency displacement so that it is possible todetermine the wind speed in the direction of the beam axis. Themeasurements can be carried out at various measurement locations alongthe beam. Owing to the sensitivity of such measurements with respect toexternal influences, in particular owing to the possibility of externalsignals impairing these measurements, in order to evaluate theoccurrence of the wind at a location, the wind properties areadditionally measured by means of at least one anemometer, which isarranged on a meteorological mast in the region of the remote windmeasurement device.

The wave beams emitted form a conical or triangular shape in order toobtain a linearly independent set of speed values which are measuredalong the beam axes, so that the determination of the wind speed ispossible in any direction. Consequently, this measurement is connectedwith a spatial averaging which involves the addition and subtraction ofmeasurement values which are measured along the beams at differentmeasurement locations. In the event of occurrences of turbulence of theair at the measurement locations, this averaging provides windproperties which differ from wind properties measured by means of ananemometer and a wind vane since, using the anemometer and the windvane, the wind properties are measured at a single spatial point. Thetwo wind properties can consequently be compared with each other only ina limited manner.

A meteorological measurement arrangement is therefore desired which

-   -   can be produced in a cost-effective manner and transported and        installed in a simple manner,    -   in particular requires no permission from any Federal Aviation        Administration and consequently preferably has a maximum height        of less than 60 m,    -   can supply the measurement data, which are accurate in relation        to standard anemometer measurements, so that the measurement        data can be recognised in particular by credit institutes,    -   enables measurements of the wind speed at different heights,    -   enables measurements at and/or above the hub height of wind        turbines, which in particular exceeds 60 m,    -   is insensitive with respect to external sources of disruption,        and    -   is more secure with respect to theft and vandalism than        ground-based measurement systems.

US 2010/0195089 A1 discloses a wind anemometer having a light source foremitting pulsed light, a receiver for receiving light back-scattered atparticles conveyed through the air for each light pulse and a processorfor determining the location of the particles with respect to theanemometer and for estimating the wind speed using location changes ofthe particles over at least one period of time. The anemometer may beorientated horizontally so that the pulsed light can be transmittedforwards from the wind turbine. Alternatively, the anemometer may beorientated in a vertical manner so that the pulsed light can betransmitted in an upward direction from the wind turbine. Thetransmitted light and the received light may travel over a common pathor also over separate paths. Owing to the use of a plurality ofanemometers, a three-dimensional wind speed can be determined.Furthermore, the anemometer may be arranged on a meteorological mast.

However, the wind speeds provided by the anemometer cannot be verifiedso that implausible measurements cannot be recognised. This uncertaintyhas to be taken into account with the anemometer, to the detriment ofthe measurement precision thereof.

Based on this, an object of the invention is to develop a meteorologicalmeasurement arrangement of the type mentioned in the introduction insuch a manner that the measurement of wind properties is possible atcomparatively low costs, even at relatively great heights, with arelatively high level of precision.

This object is achieved according to the invention with a meteorologicalmeasurement arrangement according to claim 1. Preferred developments ofthe invention are set out in the dependent claims.

The meteorological measurement arrangement according to the invention,in particular for establishing the occurrence of wind, comprises atleast one meteorological mast which extends from a substrate in anupward direction and which carries one or more wind measurement devices,the or at least one of the wind measurement devices being arranged inthe region of the upper mast tip and being constructed as a remote windmeasurement device, by means of which wind properties are measured orcan be measured at one or more remote measurement locations which arelocated above and with spacing from the remote wind measurement device,at least one other of the wind measurement devices being arranged in theregion of the upper mast tip in close proximity to the remote windmeasurement device and being constructed as a local wind measurementdevice, by means of which wind properties at the location of this windmeasurement device can be measured in the vicinity of the remote windmeasurement device.

Using the remote wind measurement device, it is possible to measure thewind properties at heights which are above the mast height. For example,wind properties can be measured at heights of 100 m or more, althoughthe mast height is, for example, only 60 m or less. Since the remotewind measurement device is located in the region of the mast tip andconsequently at a relatively high position, in particular is arranged ina state remote from the substrate, a measurement carried out with theremote wind measurement device is also substantially more precise than aconventional remote wind measurement, which is carried out from thelevel of the substrate. The other wind measurement device is alsoreferred to as a reference wind measurement device. In particular, thewind properties measured by the remote wind measurement device can beevaluated by taking into account the wind properties measured by thereference wind measurement device. For example, a plausibilityverification and/or a correction of the wind properties measured by theremote wind measurement device and/or a calibration of the remote windmeasurement device and/or the measurements carried out by means of theremote wind measurement device can be carried out. Consequently, theinvention affords the possibility of measuring the wind properties atrelatively great heights in a relatively precise manner. In particular,using the remote wind measurement device, the wind properties can bemeasured at one or more heights, which are at and/or above the hubheight of a wind turbine. Furthermore, the mast height is preferably ator below 80 m or 100 m so that the cost increase linked with a greatermast height can be prevented. Preferably, the mast height isapproximately 60 m and/or below 60 m so that, in the USA, it is notnecessary to acquire permission from the Federal Aviation AdministrationFAA.

The wind properties measured by the remote wind measurement devicepreferably include the wind speed and/or the wind direction.

The “wind speed” is preferably a vectorial variable with spatialcomponents. Preferably, the wind speed comprises one vertical and twohorizontal components. When the wind speed is considered in a vectorialmanner, the wind speed consequently also comprises information relatingto the wind direction. The vertical component of the wind speed is alsoreferred to as vertical wind speed. Preferably, a horizontal wind speedis further defined which comprises the two horizontal components of thewind speed. However, it is also possible to define a horizontal windspeed which comprises only one of the horizontal components of the windspeed. The latter may be advantageous when only one of the horizontalcomponents of the wind speed is of interest.

Alternatively, it is possible to consider the value of the vectorialwind speed as the “wind speed” (for example, when measuring the windspeed with a cup anemometer). In this case, the wind directionconstitutes additional information. Preferably, the vectorial wind speedand/or the vertical wind speed and/or the horizontal wind speed can beformed by the wind direction and the value of the wind speed.

The mast extends from the substrate in particular in a vertical orsubstantially vertical upward direction. The remote wind measurementdevice is preferably arranged with vertical spacing above the substrate.Furthermore, by means of the remote wind measurement device, the windproperties are preferably measured with a vertical or substantiallyvertical spacing with respect to the remote wind measurement device. Theremote measurement locations are preferably located above and withspacing from the mast tip.

According to an embodiment of the invention, the remote wind measurementdevice comprises a LIDAR system or a SODAR system. The term “SODAR”stands for “Sonic Detection and Ranging” and refers to an acousticremote measurement method. The term “LIDAR” stands for “Light Detectionand Ranging” and refers to an optical remote measurement method. Thesesystems are known from the prior art and form a preferred embodiment forthe remote wind measurement device. In particular, by means of theremote wind measurement device, the wind properties are established atdifferent heights so that the remote measurement locations are alsolocated at different heights.

The reference wind measurement device is arranged in the region of theupper mast tip and is constructed as a local wind measurement device, bymeans of which wind properties are measured or can be measured at thelocation of this wind measurement device. Since both the remote windmeasurement device and the reference wind measurement device are locatedin the region of the upper mast tip, the reference wind measurementdevice is arranged in close proximity to the remote wind measurementdevice. Consequently, using the reference wind measurement device, thewind properties can be measured in the vicinity of the remote windmeasurement device. In the event of an evaluation of the wind propertiesmeasured by the remote wind measurement device, taking into account thewind properties measured by the reference wind measurement device, theactual wind properties at the remote measurement location(s) can bedetermined with greater precision since the wind properties at thelocation or in the region of the remote wind measurement device areknown. The reference wind measurement device is preferably arrangedabove the remote wind measurement device. It can consequently beexcluded that a measurement carried out by means of the reference windmeasurement device is impaired by the remote wind measurement device.Such an impairment may be brought about, for example, in that thereference wind measurement device is located in the lee of the wind ofthe remote wind measurement device. The wind properties measured by thereference wind measurement device preferably comprise the wind speedand/or the wind direction. Furthermore, these wind properties may alsoinclude the air temperature and/or the air pressure.

According to a development of the invention, at least one other of thewind measurement devices is arranged below the remote wind measurementdevice and is constructed as a local wind measurement device, by meansof which wind properties at the location of this wind measurement deviceare measured or can be measured. The additional wind measurement deviceis also referred to as a lower wind measurement device. Using the lowerwind measurement device, the wind properties can advantageously bemeasured at a height which is below the hub height of a wind turbine.The wind properties measured by the lower wind measurement devicepreferably include the wind speed and/or the wind direction.Furthermore, these wind properties may also include the air temperatureand/or the air pressure. Advantageously, a plurality of additional orlower wind measurement devices are provided at different heights on themast. Preferably, the plurality of additional or lower wind measurementdevices are each arranged below the remote wind measurement device. Inparticular, the plurality of additional or lower wind measurementdevices are each constructed as local wind measurement devices.

The term “local wind measurement device” is used in particular to referto a wind measurement device which can measure wind properties at alocation at which the local wind measurement device is arranged. Thesewind properties preferably include the wind speed and/or the winddirection. These wind properties may further also include the airtemperature and/or the air pressure. Preferably, each of the local windmeasurement devices comprises a wind direction measurement device and/ora wind direction measurement device (wind direction transmitter). Therespective wind speed measurement device may comprise, for example, ananemometer, in particular a cup anemometer. Furthermore, the respectivewind direction measurement device may comprise, for example, a windvane. The respective wind speed measurement device and the respectivewind direction measurement device may form separate measurement devices.Alternatively, the respective wind speed measurement device and therespective wind direction measurement device may also be formed by asingle measurement device which, for example, comprises an ultrasoundanemometer. Each of the local wind measurement devices may, as required,further comprise a temperature transmitter and/or a pressuretransmitter. The respective pressure transmitter is, for example, formedby a barometer. Furthermore, the respective temperature transmitter isformed, for example, by a thermometer. As already described above, inparticular the other wind measurement device and/or the additional windmeasurement device(s) is/are constructed as a local wind measurementdevice.

The other wind measurement device and/or the additional wind measurementdevice(s) preferably each comprise an anemometer and/or a wind directiontransmitter, such as, for example, a wind vane and/or a temperaturetransmitter and/or a pressure transmitter. With the or with each of theanemometer(s), it is possible to establish in particular the wind speedat the location of the respective wind measurement device. Preferably,with the or with each of the anemometer(s), it is possible to measureboth the wind speed and the wind direction at the location of therespective wind measurement device. The or each of the anemometers mayconsequently comprise a wind direction transmitter. With the or witheach of the wind direction transmitter(s), it is possible to establishin particular the direction of the wind at the location of therespective wind measurement device. This is advantageous in particularwhen the anemometer(s) can only provide the wind speed. With the or witheach of the temperature transmitter(s), the temperature of the air atthe location of the respective wind measurement device can preferably bemeasured. With the or with each of the pressure transmitter(s), the airpressure at the location of the respective wind measurement device canadvantageously be measured.

According to a development of the invention, the remote wind measurementdevice is connected to at least one recording device, the windproperties measured by the remote wind measurement device beingtransmitted in the form of measurement data to the recording device, bymeans of which the measurement data are recorded, in particular stored.Preferably, the other wind measurement device and/or the additional windmeasurement device(s) is/are connected to the recording device, the windproperties measured by the other wind measurement device and/or theadditional wind measurement device(s) being transmitted in the form ofmeasurement data to the recording device, by means of which thosemeasurement data are recorded, in particular stored. The recordingdevice is preferably arranged on the mast. In particular, the recordingdevice is carried by the mast.

The wind measurement device(s) may be connected to an externalelectrical power supply and be supplied with electrical power thereby.The same applies to the recording device. However, the mast preferablycarries a solar cell arrangement by means of which the wind measurementdevice(s) can be supplied with electrical power. Consequently, it ispossible to also operate the meteorological measurement arrangement whenthere is no external power supply. According to a development of theinvention, the mast carries a battery arrangement by means of which thewind measurement device(s) can be supplied with electrical power. Anindependence from an external power supply can also be achieved thereby.Advantageously, the battery arrangement is electrically connected to thesolar cell arrangement and can be electrically charged thereby.Preferably, the battery arrangement comprises one or more chargeablebatteries or accumulators.

The substrate is preferably formed by the ground. The mast preferablystands on the substrate. Furthermore, the mast may stand on a foundationand/or be connected to the ground by means of the foundation.Advantageously, the mast is a tiltable mast, which is constructed inparticular by means of upward pivoting so that it can be completelypreassembled in the horizontal state. The mast is preferably retained bymeans of a plurality of retention cables, which are secured both to themast and to the substrate. The mast may be constructed as a lattice-likeconstruction or in a tubular manner. In particular, the end of the mastfacing away from the substrate forms the mast tip. The mast preferablyforms an elongate member whose particular direction is directed upwardsfrom the substrate, in particular in a vertical or substantiallyvertical direction. The mast is preferably a stationary mast. The term“stationary” refers in particular to a measurement time period in whichthe wind properties are measured by means of the wind measurementdevice(s) so that the mast is stationary during or at least during themeasurement of the wind properties using the wind measurement device(s).In particular, the mast forms neither a wind turbine, nor a portion of awind turbine. However, the mast may be provided in addition to and/oralongside one or more wind turbines. In particular, the meteorologicalmast is consequently a mast which is external with respect to the windturbine.

The meteorological measurement arrangement according to the invention ispreferably a stationary measurement arrangement. The term “stationary”in particular refers to a measurement time period in which the windproperties are measured by means of the wind measurement device(s) sothat the measurement arrangement is stationary during or at least duringthe measurement of the wind properties using the wind measurementdevice(s). The measurement arrangement according to the invention ispreferably a measurement arrangement which is external with respect tothe wind turbine.

According to a development of the invention, there is provided acompensation device, by means of which movements of the mast tiprelative to the substrate can be detected. Such movements may be broughtabout, for example, by means of wind which acts on the mast. Themovements of the mast tip lead to movements of the remote windmeasurement device relative to the substrate, whereby the windproperties measured by the remote wind measurement device can beinfluenced and/or distorted. Using the compensation device, suchinfluences and/or distortions of the wind properties measured by theremote wind measurement device can preferably be compensated for. Thecompensation device is in particular arranged in the region of the uppermast tip and is preferably securely connected to the mast.Advantageously, the compensation device is coupled to the remote windmeasurement device and/or to an evaluation unit which is connectedthereto and/or integrated therein. The compensation device comprises inparticular at least one movement measurement device which is arranged inthe region of the upper mast tip and which is constructed, for example,as an acceleration measurement device or as a camera.

Using the camera, it is possible to detect, for example, movements ofthe mast tip relative to a reference location provided on the substrateand/or reference object.

According to an embodiment of the invention, the remote wind measurementdevice comprises a wave receiver and a wave transmitter, by means ofwhich waves are or can be transmitted into the atmosphere, at least aportion of which is scattered and/or reflected in the atmosphere. Atleast a portion of the scattered and/or reflected waves is preferablyreceived by the wave receiver. The wave transmitter and the wavereceiver are in particular arranged in close proximity to one another.The wave transmitter and the wave receiver are preferably combined toform a transmission/receiving unit. The waves are preferablyelectromagnetic waves or sound waves. Consequently, the remote windmeasurement device comprises or forms in particular a LIDAR system or aSODAR system. The waves are preferably transmitted by the wavetransmitter in a vertical direction or upwards in a direction inclinedwith respect to the vertical direction. The waves transmitted by thetransmitter are in particular scattered and/or reflected atinhomogeneities present in the air, for example, on particles carried bythe air. The inhomogeneities or particles are excited by the waves andthereby themselves become the radiation source. If the inhomogeneitiesor particles move together with the air relative to the wave receiver,the waves which are received thereby and which have been scatteredand/or reflected by the particles, owing to the Doppler effect, have adifferent frequency from the waves transmitted by the transmitter, thefrequency difference (Doppler frequency displacement) between thetransmitted and received waves describing the speed of theinhomogeneities or particles relative to the wave receiver andconsequently characterising the wind speed at the location of theinhomogeneities or particles. In particular, the waves transmitted bythe transmitter are scattered and/or reflected in one or more volumeranges of the atmosphere located above the remote wind measurementdevice, the volume range(s) each forming one of the remote measurementlocations. The height of the remote measurement locations can preferablybe adjusted and/or varied by means of the remote wind measurementdevice.

Preferably, the waves are collimated by the transmitter to form one ormore beams. According to an embodiment of the invention, the beams aretransmitted upwards by the transmitter in different directions inclinedwith respect to the vertical direction so that the beams together definea geometry which tapers in particular in the direction towards the mast.The geometry is preferably conical or triangular. The aperture angle ofthe geometry is, for example, between 20° and 30° in the case of soundwaves and between 50° and 60° in the case of electromagnetic waves. Thegeometry formed by the beams is preferably symmetrical relative to thevertical direction. In the case of a SODAR system, such a measurementmay also be referred to as a monostatic measurement. Preferably,measurement values obtained from waves received by the receiver andscattered and/or reflected by means of volume ranges or remotemeasurement locations which are located on different beams and whichhave the same vertical spacing with respect to the remote windmeasurement device are each associated with a group by an evaluationunit which is connected to or integrated in the remote wind measurementdevice and/or in each case evaluated to form a horizontal wind speed anda vertical wind speed. Each of these groups consequently comprises aplurality of measurement values from a plurality of remote measurementlocations or volume ranges which are horizontally spaced apart from eachother and which have the same vertical spacing with respect to theremote wind measurement device. A vertical wind speed and a horizontalwind speed can thereby be obtained in particular for each group. Usingthe remote wind measurement device, consequently, it is possible topreferably establish both the vertical component of the wind speed andthe horizontal component of the wind speed at the or at each of theremote measurement locations.

According to a development of the invention, there is provided a secondmeteorological mast which extends in an upward direction from thesubstrate and which is spaced apart from the (first) meteorological mastand which carries at least one wave receiver (second wave receiver)which is arranged in the region of the upper mast tip thereof and bymeans of which at least a portion of the scattered and/or reflectedwaves is received. The masts are preferably spaced apart from each otherin a horizontal direction. In particular, the second mast extendsupwards from the substrate in a vertical direction. Consequently, thewind speed and the wind direction can preferably be detected in alimited vertical layer. In particular, the waves emitted by thetransmitter are collimated, preferably by means of the transmitter, toform a single beam which is discharged vertically upwards. In the caseof a SODAR system, such a measurement may also be referred to as abistatic measurement. It is further possible with the wave receiver ofthe remote wind measurement device (first wave receiver) to carry out amonostatic measurement and additionally carry out a bistatic measurementwith the second wave receiver.

According to a development of the invention, the second mast carries aremote wind measurement device (second remote wind measurement device)which comprises the second wave receiver and preferably also a wavetransmitter (second wave transmitter). In particular, the second remotewind measurement device is arranged in the region of the upper mast tipof the second mast. Preferably, by means of the second wave transmitter,in particular in a vertical or in a substantially vertical direction,waves are transmitted into the atmosphere, at least a portion of whichis scattered and/or reflected in the atmosphere. Advantageously, atleast a portion of the scattered and/or reflected waves of the secondwave transmitter is received by means of the second wave receiver.Preferably, at least a portion of the scattered and/or reflected wavesof the second wave transmitter is received by means of the first wavereceiver. Preferably, at least a portion of the scattered and/orreflected waves of the second wave transmitter is received by means ofthe wave receiver. The wave transmitters may transmit at the same timeor alternately. Advantageously, the second remote wind measurementdevice is constructed in the form of a LIDAR system or SODAR system. Itis consequently possible to carry out a monostatic measurement with eachof the remote wind measurement devices. Additionally or alternatively,it is possible to carry out a bistatic measurement with each of theremote wind measurement devices in combination with the other remotewind measurement device. The measurement precision of the meteorologicalmeasurement arrangement according to the invention can thereby befurther increased. The masts are preferably constructed so as to beidentical.

According to a development of the invention, the remote wind measurementdevices emit waves of different frequency so that the frequency of thewaves emitted by one of the remote wind measurement devices differs fromthe frequency of the waves emitted by another of the remote windmeasurement devices. Better separation of the signals is therebypossible. Preferably, the frequency difference between the wavestransmitted is greater than twice the maximum anticipated Dopplerfrequency displacement of the scattered and/or reflected waves.Furthermore, the waves are preferably emitted from the remote windmeasurement devices in a temporally pulsed manner. Preferably, at leastat the beginning of each wave pulse (also referred to here as the wavepacket), a synchronisation signal is transmitted from each of the remotewind measurement devices to the other remote wind measurement device,respectively, which subsequently preferably measures the period of timeuntil the arrival of the respective associated scattered and/orreflected wave pulse. Advantageously, a synchronisation signal is alsotransmitted from each of the remote wind measurement devices to theother remote wind measurement device at the end of each wave pulse,respectively.

The invention further relates to the use of at least one meteorologicalmeasurement arrangement according to the invention for establishing theoccurrence of the wind and/or the wind conditions at or in a location orarea which is in particular free from wind turbines, and at or in which,after the beginning or the completion of the establishment of theoccurrence of the wind, one or more wind turbines is/are constructed.The use according to the invention may be developed in accordance withall the embodiments explained in connection with the meteorologicalmeasurement arrangement according to the invention.

However, the meteorological measurement arrangement according to theinvention may also be used in an existing wind park in order to monitorthe occurrence of the wind and/or the wind conditions. The inventionconsequently further relates to a wind park having a plurality of windturbines and at least one meteorological measurement arrangementaccording to the invention. The wind park according to the invention maybe developed in accordance with all the embodiments explained inconnection with the meteorological measurement arrangement according tothe invention.

The invention is described below with reference to preferred embodimentsand the drawings, in which:

FIG. 1 is a schematic illustration of a meteorological measurementarrangement according to a first embodiment of the invention,

FIG. 2 is another schematic illustration of the measurement arrangementaccording to the first embodiment and a wind turbine,

FIG. 3 is a schematic illustration of the remote wind measurement deviceaccording to the first embodiment,

FIG. 4 is a schematic illustration of a remote wind measurement deviceof a meteorological measurement arrangement according to a secondembodiment of the invention, and

FIG. 5 is a schematic illustration of a meteorological measurementarrangement according to a third embodiment of the invention.

In FIGS. 1 to 3, different views and partial views of a meteorologicalmeasurement arrangement 1 according to a first embodiment of theinvention can be seen, a meteorological mast 10 standing on a substrate15 which is formed by the ground and extending upwards therefrom in avertical direction z. The mast 10 is retained in its vertical positionby means of retention cables 29 which are secured both to the mast 10and to the substrate 15. Furthermore, the mast 10 is constructed in alattice-like manner. Alternatively, however, the mast 10 may also beconstructed in a tubular manner. The mast 10 is in particular a tiltablemast, which is constructed by being pivoted upwards into the positionwhich can be seen in FIG. 1, which is preferably carried out with theassistance of a suitable lifting mechanism. The overall height of themast 10 is in particular below 60 m.

There are positioned on the mast 10, at different heights, local windmeasurement devices 201 and 202, which each measure the wind speed andthe wind direction at the respective location thereof and are referredto as lower wind measurement devices. Furthermore, in the region of theupper mast tip 17 facing away from the substrate 15, a remote windmeasurement device 100 is arranged and secured to the mast 10. Theremote wind measurement device 100 transmits waves into the air (or intoa fluid or into another medium), the waves being collimated to formbeams. These waves are scattered and/or reflected on inhomogeneities inthe air (or in the fluid) so that at least a portion of the scatteredand/or reflected waves returns to the remote wind measurement device100, which waves are received thereby. By means of evaluation of theDoppler frequency displacement of the back-scattered and/orback-reflected waves, the remote wind measurement device 100 determinesthe air speed (or fluid speed) at the location of the scattering and/orreflection (measurement location). The waves may be electromagneticwaves or sound waves, the remote wind measurement device 100 forming aSODAR system in the case of sound waves. In the case of electromagneticwaves, the remote wind measurement device 100 forms a LIDAR system.

The measurement arrangement further comprises a local wind measurementdevice 200 which is arranged in the region of the mast tip 17 close tothe wind measurement device 100 and is secured to the mast 10, and whichmeasures the wind speed and the wind direction at the location thereofand which is referred to as a reference wind measurement device. Thereference wind measurement device 200 is arranged above the remote windmeasurement device 100 so that measurements carried out by means of thereference wind measurement device 200 are not impaired by means ofturbulent flows or turbulence produced by means of the remote windmeasurement device 100. The reference wind measurement device 200provides reference values for the wind speed and the wind direction inthe vicinity of the remote wind measurement device 100 so that thesereference values are used to calibrate the measurements carried out bymeans of the remote wind measurement device 100.

If the remote wind measurement device 100 is constructed as a SODARsystem, a sound reflector 40 is secured to the mast 10. The soundreflector 40 is preferably located in a position between the remote windmeasurement device 100 and the mast-side securing locations of theretention cables 20 so that it forms a sound shield for the remote windmeasurement device 100 against sound which may be produced by theretention cables 20 in conjunction with the wind.

There is further secured to the mast 10 a lightning conductor 30 whichextends upwards beyond the remote wind measurement device 100 so thatthe measurement arrangement 1 can be protected against lightningstrikes.

In the vicinity of the substrate 15, there is secured to the mast 10 asolar cell arrangement 60 which provides electrical power in order tooperate the measurement arrangement 1. This is particularly advantageousat locations at which no external power supply is available.Furthermore, there is secured to the mast 10 a switch cabinet 50 whichcomprises batteries 51 and/or other devices for storing electricalenergy so that uninterrupted power supply for the local wind measurementdevices 200, 201 and 202 and/or the remote wind measurement device 100and/or other electrical devices of the mast 10 can be ensured (forexample, at night). The switch cabinet 50 further comprises a recordingdevice 52 for recording the measured values for the wind speeds and winddirections which are measured by all the wind measurement devices 100,200, 201 and 202 of the mast 10. The recording device 52 is alsoreferred to as the first data recording device.

As can be seen from FIG. 2, the remote wind measurement device 100 emitswaves along beams 105 and 106 which describe a conical or triangulargeometry 120′ whose aperture angle α is typically between 20° and 30°with a SODAR system and between 50° and 60° with a LIDAR system. Themeasurements are carried out in volume ranges 101, 101′, 102 and 102′which are arranged along the beams 105 and 106. Since a measurement ofthe wind speed is carried out only along the beam direction of therespective beam, several measurements are carried out, preferably at thesame height, and provide the wind speed in the horizontal direction xand the wind speed in the vertical direction y. To this end, there arefunctionally combined to form a group the volume ranges of the beams 105and 106 which preferably have the same or substantially the same spacingalong the beams 105 and 106 with respect to the remote wind measurementdevice 100, such as, for example, the volume ranges 101 and 101′. Thehorizontal spacing increases between the volume ranges of the groupswith increasing spacing with respect to the remote wind measurementdevice 100. As this spacing increases, the precision of the horizontaland vertical wind speeds derived may decrease owing to occurrences ofwind turbulence. In particular, such occurrences of turbulence mayreduce the correlation between the values measured in the volume ranges.However, these problems may be overcome by means of long-term samplingand averaging.

With conventional remote wind measurement devices, which are arranged atthe height of the substrate 15, the horizontal spacing between thevolume ranges prevents a “clean” and direct comparison of the wind speedderived from the remote wind measurement device with a wind speed whichis measured in a single spatial location by means of a local windmeasurement device. According to the invention, owing to the proximityof the remote wind measurement device 100 with respect to the referencewind measurement device 200, this obstacle is overcome, which can beparticularly attributed to two reasons. Firstly, the spacing between thereference wind measurement device 200 and the lowest group of volumeranges 101 and 101′ is small. Secondly, the horizontal spacing betweenthe volume ranges 101 and 101′ of the lowest group is small owing to itsproximity with respect to the remote wind measurement device 100.Consequently, there is a close correlation between the measurementvalues provided by the remote wind measurement device 100 and themeasurement values provided by a local wind measurement device so thatthe measurement values provided by the remote wind measurement device100 have a higher level of acceptability. In particular, the measurementvalues provided by the remote wind measurement device 100 are suitablefor the evaluation of the occurrence of wind at the location of themeasurement arrangement 1 and can consequently be considered to beaccurate and valid by persons responsible for the evaluation of theoccurrence of wind and accreditation institutes.

A modern multi-megawatt wind turbine is schematically illustrated inFIG. 2 and designated 300. Such a wind turbine has a hub height h2 inthe range from 80 m to 100 m above the substrate 15. Since the costs formeteorological masts having mast heights of 80 m or more increaseconsiderably, such high masts are unpopular. Although it is known fromthe prior art to carry out wind measurements at heights below h2 and toextrapolate the measurement values obtained to greater heights, thisextrapolation leads to uncertainties and errors with the estimatedvalues for the wind speed and the wind direction. According to theinvention, these uncertainties and errors are thereby prevented or atleast substantially reduced by the remote wind measurement device 100being arranged at a height which corresponds or at least substantiallycorresponds to the mast height h1. Consequently, more precisemeasurements of the wind speed and the wind direction are possible atthe height h2. Furthermore, more precise measurements of the wind speedand the wind direction are also possible at the height h3 whichcharacterises the upper end of the rotor 310 of the wind turbine 300. Inaddition, the mast 10 may be kept below a height from which permissionof the US Federal Aviation Administration FAA is required.

The arrangement of the remote wind measurement device 100 at the tip 17of the mast 10 reduces the spacing of the remote wind measurement device100 with respect to the volume range which is furthest away and which isused for a measurement. Consequently, the radiation capacity of theremote wind measurement device 100 can also be reduced so that it can beconstructed so as to have less power and/or so as to be smaller than aSODAR or LIDAR system which is arranged on the substrate 15. If theremote wind measurement device 100 is constructed as a SODAR system, thereduced spacing with respect to the volume ranges further enables ahigher operating frequency so that the geometric dimensions of theremote wind measurement device (owing to the smaller acousticwavelength) can be reduced and the influence of background interferences(owing to the higher frequency) can be reduced. The latter leads inparticular to a better signal-to-noise ratio. In addition, thearrangement of the remote wind measurement device 100 on the mast tip 17increases the spacing between the remote wind measurement device 100 andsources of background noises present at the substrate level. Anotheradvantage of the spacing of the remote wind measurement device 100 withrespect to the substrate 15 is the increased security with respect totheft and vandalism.

FIG. 3 is a schematic view of the remote wind measurement device 100which has a transmission and receiving unit 110 by means of which wavescan be produced and received. There is further provided an evaluationunit 130 by means of which measurement data established from theback-scattered waves are formed into a first wind speed and directionfor each group of volume ranges. An evaluation unit 120 receives thesignals provided by the reference wind measurement device 200 and formsthem into a second wind speed and direction, a comparison and adjustmentunit 140 being provided by means of which the first wind speed anddirection, which is associated with the lowest group of volume ranges101 and 101′, is compared with the second wind speed and direction.Furthermore, the comparison and adjustment unit 140 may modify orcorrect the wind speed and direction for all groups of volume ranges onthe basis of this comparison. Furthermore, the remote wind measurementdevice 100 comprises an acceleration measurement device 160, by means ofwhich in particular a movement of the mast 10 or the mast tip 17 can beestablished. The acceleration measurement device 160 is used tocompensate for disruptive influences which influence the windmeasurements carried out by the remote wind measurement device 100 andwhich are brought about by movements of the mast 10. In addition or asan alternative to the acceleration measurement device 160, the currentorientation and speed of the remote wind measurement device 100 can beestablished by means of a camera, which is arranged in or in theproximity of the remote wind measurement device 100 and which is focusedon a predetermined reflector or on another predetermined optical targetclose to the mast base 18. The orientation and speed of the remote windmeasurement device 100 can consequently be established by means of amovement of the image of the reflector or target on the light-sensitiveplane of the camera. The camera is in particular an optical digitalcamera. Using the camera, a movement of the mast 10 can consequently beestablished.

The values measured by means of the remote wind measurement device 100and preferably also by means of the reference wind measurement device200 are supplied to the first data recording device 52 by means of acommunication line 150. These measured values represent in particularinformation relating to the wind field above the remote wind measurementdevice 100.

FIG. 4 is a schematic view of a remote wind measurement device 100 of ameteorological measurement arrangement according to a second embodimentof the invention, features which are identical or similar to the firstembodiment being given the same reference numerals as in the firstembodiment. In particular, the remote wind measurement device accordingto FIG. 4 may replace the remote wind measurement device according toFIG. 3. The remote wind measurement device 100 comprises a secondevaluation unit 170, by means of which measurement data supplied via thecommunication line 150 are collected from the remote wind measurementdevice 100 and stored. Furthermore, measurement data can be collectedand stored from other wind measurement devices 201, 202, 203, etc.,which are arranged at various locations of the mast 10 and which areeach preferably constructed as local wind measurement devices. Themeasured data may be both stored locally and transmitted to an externalreceiver, for example, by means of a wireless communication system. Theremote wind measurement device 100 further comprises a light signaltransmitter 180 which may be required for legal reasons. The advantageof the integration of the data storage and/or the light signaltransmitter 180 in the remote wind measurement device 100 in particularinvolves the consolidation and common use of common systems in a singleunit so that redundancies and costs can be reduced. Examples of suchcommon systems are, for example, temperature controllers for operationin cold or warm weather, direct-current voltage sources, wirelesscommunication systems, internal temperature and humidity sensors,lightning protection switches and the external protective housing. As anadditional advantage, there may be provided in the evaluation unit 170 amonitoring system by means of which the operating state and/or thefunctional state of the remote wind measurement device 100—andpreferably the local wind measurement devices—can be monitored and canbe transmitted to the or an external receiver in the form of a report.Preferably, the monitoring system may interrogate the operating state ofeach component, including each wind measurement device, and thesub-components of the remote wind measurement device 100 and provide areport relating to the operating state of the entire mast system to theexternal receiver. This report may be carried out, for example, by meansof the wireless communication system. For further description of thesecond embodiment, reference is made to the description of the firstembodiment.

In the previous embodiments, the scattering operation produces reflectedwaves, which propagate from the location of the scattering in severaldirections. The remote wind measurement device 100 comprises a wavetransmitter 115 and a wave receiver 116, which is arranged in closeproximity to the wave transmitter 115, both the transmitter 115 and thereceiver 116 being arranged in the remote wind measurement device 100.Owing to this proximity, the remote wind measurement device 100 operateswith signals which are back-scattered from atmospheric inhomogeneitiesso that the receiver 116 in particular receives only those scatteredwaves which extend in one direction, which is opposed or substantiallyopposed to the radiation direction of the waves transmitted by means ofthe transmitter 115. In the case of sound waves, such a remote windmeasurement device is known as a monostatic SODAR system.

However, it is also possible to carry out a measurement on the basis ofwaves which are scattered in an oblique manner. Waves which arescattered in an oblique manner are intended to be defined as waves whichare scattered in a direction which deviates from the 180° direction ofthe back-scattered waves. In the case of waves which are scattered in anoblique manner, the wave transmitter and the wave receiver are arrangedat different spatial positions, which is known from the prior art as abistatic system. The use of waves which are scattered in an obliquemanner affords in particular the two following advantages: on the onehand, the scattered signal strength is substantially higher than withback-scattered waves, since the sound waves which are scattered in anoblique manner are produced in particular by energetically vertical(that is to say, speed-based) turbulence movements, whereas theback-scattered sound waves are produced in particular only by the weakerdensity disturbances within the turbulence field. On the other hand, inplace of the beams 105 and 106 which form the conical or triangulargeometry 120, a single vertical beam 420 can be used so thatmeasurements at substantially point-like measurement locations 101 and102, etc., can be carried out along the beam 420 at different heights(see FIG. 5). The single beam 420 defines a narrow geometry inparticular with respect to the geometry 120.

FIG. 5 is a schematic view of a meteorological measurement arrangement 1according to a third embodiment of the invention, features which areidentical or similar to the previous embodiments being given the samereference numerals as in the previous embodiments. According to thethird embodiment, the concept of a bistatic system having a single wavetransmitter is expanded to a new multistatic system which comprises twoor more wave transmitters. A remote wind measurement device 100 which isarranged in the region of the mast tip of a first meteorological mast 10comprises a first wave receiver 116 and a first wave transmitter 115which produces a first wave beam 420. The first beam 420 extends inparticular upwards in a vertical direction z. A second remote windmeasurement device 500 which is arranged in the region of the mast tipof a second meteorological mast 12 comprises a second wave receiver 530and a second wave transmitter 510 which produces a second beam 520. Thesecond beam 520 extends in particular upwards in a vertical direction z.Waves which are emitted by the first wave transmitter 155 and which arescattered by means of atmospheric inhomogeneities along the first beam420 at locations 101, 102, etc., are received both by the first wavereceiver 116 as back-scattered waves and by the second wave receiver 530as waves which are scattered in an oblique manner. At the same time,waves which are emitted by the second wave transmitter 510 and which arescattered by means of atmospheric inhomogeneities along the second beam520 at locations 501, 502, etc., are received both by the second wavereceiver 530 as back-scattered waves and by the first wave receiver 116as waves which are scattered in an oblique manner. In order to associatea specific spatial location along the wave beam with each of the signalswhich are scattered in an oblique manner, the following measures are inparticular implemented:

1. The process of the wave production by means of the first and thesecond wave transmitter 115 and 510 is carried out in a temporallypulsed manner so that wave packets with a limited spatial expansion areproduced, which are propagated in the direction of the respective wavebeam 420 or 520.2. At the beginning and at the end of the respective wave packetproduction, a synchronisation signal is in each case transmitted fromthe respective wave transmitter to the other wave receiver (that is tosay, the wave transmitter 115 transmits a synchronisation signal to thewave receiver 530 and the wave transmitter 510 transmits asynchronisation signal to the wave receiver 116). The synchronisationsignal is preferably transmitted in the form of electromagnetic waves.3. The period of time between the respective synchronisation signal andthe arrival of the scattered wave signals is measured and used tocalculate the spatial position (measurement location) along therespective beam, from which the scattered signal originates.

In order to make it easier for the wave receiver 116 to differentiatebetween signals back-scattered from the beam 420 and wave signalsscattered in an oblique manner by the beam 520, there is preferablyselected for the frequency of the waves of the beam 520 a frequencywhich differs from the frequency of the waves of the beam 420 by a valuewhich is in particular greater than twice the Doppler frequencydisplacement, which is anticipated as a maximum for the measurementoperation. This frequency separation prevents a frequency overlap ofscattered signals of the beam 420 and the beam 520. If three or morebeams are used, the frequency of each beam is preferably selected insuch a manner that no frequency overlap can occur between all thescattered signals. Apart from this, the two masts 10 and 12 arepreferably constructed in an identical manner. For further descriptionof the third embodiment, reference is made to the description of theprevious embodiments.

Finally, it should be mentioned that a multistatic system using threebeams which are located at the corners of a triangle enables themeasurement of the Doppler frequency displacement in two independenthorizontal directions so that the measurement of all three spatialcomponents of the wind speed is possible. The beams preferably eachextend in a vertical direction.

LIST OF REFERENCE NUMERALS

-   1 Meteorological measurement arrangement-   10 Meteorological mast-   12 Meteorological mast-   15 Substrate-   17 Mast tip-   18 Mast base-   20 Retention cable-   30 Lightning conductor-   40 Sound reflector-   50 Switch cabinet-   51 Batteries-   52 Recording device-   60 Solar cell arrangement-   100 Remote wind measurement device-   101 Volume range/Measurement location-   101′ Volume range/Measurement location-   102 Volume range/Measurement location-   102′ Volume range/Measurement location-   103 Measurement location-   104 Measurement location-   105 Beam-   106 Beam-   110 Transmission/receiving unit-   115 Wave transmitter-   116 Wave receiver-   120 Evaluation unit-   120′ Geometry defined by beams-   130 Evaluation unit-   140 Comparison unit-   150 Communication line-   160 Acceleration measurement device-   170 Evaluation unit-   180 Light signal transmitter-   200 Reference wind measurement device-   201 Wind measurement device-   202 Wind measurement device-   300 Wind turbine-   310 Rotor of the wind turbine-   420 Beam-   500 Remote wind measurement device-   501 Measurement location-   502 Measurement location-   503 Measurement location-   504 Measurement location-   510 Second wave transmitter-   530 Second wave receiver-   520 Second beam-   z Vertical direction-   x Horizontal direction-   α Aperture angle of the geometry

1-33. (canceled)
 34. A meteorological measurement system comprising: ameteorological mast extending from a substrate in an upward direction; afirst wind measurement device arranged in an upper mast tip region ofthe mast and operable as a remote wind measurement device for measuringwind properties at one or more remote measurement locations in spacedrelation to the remote wind measurement device; and a second windmeasurement device arranged in the upper mast tip region in proximate tothe remote wind measurement device and operable as a local windmeasurement device for measuring wind properties at the location of thelocal wind measurement device and in the vicinity of the remote windmeasurement device.
 35. The meteorological measurement system accordingto claim 34 wherein the remote wind measurement device is selected fromthe group consisting of a LIDAR system, a SODAR system or combinationsthereof.
 36. The meteorological measurement system according to claim34, wherein the remote measurement locations are located at differentheights with respect to the location of the remote measurement device.37. The meteorological measurement system according to claim 34, whereinthe local wind measurement device provides reference values for windspeed and wind direction in the proximity of the remote wind measurementdevice for calibrating measurements from the remote wind measurementdevice.
 38. The meteorological measurement system according to claim 34,wherein the local wind measurement device is arranged above the remotewind measurement device.
 39. The meteorological measurement systemaccording to claim 34, wherein the local wind measurement devices isarranged below the remote wind measurement device.
 40. Themeteorological measurement system according to claim 34, wherein each ofthe remote and local wind measurement devices are selected from thegroup consisting of an anemometer, a wind direction indicator orcombinations thereof.
 41. The meteorological measurement systemaccording to claim 34, wherein the remote wind measurement device isconnected to at least one recording device, the wind properties measuredby the remote wind measurement device being communicated and stored tothe recording device in the form of measurement data.
 42. Themeteorological measurement system according to claim 41, wherein thelocal wind measurement device is connected to the at least one recordingdevice, the wind properties measured by the local wind measurementdevice being communicated and stored to the recording device in the formof measurement data.
 43. The meteorological measurement system accordingto claim 42, wherein the mast carries the at least one recording device.44. The meteorological measurement system according to claim 34, furthercomprising a solar cell arrangement carried by the mast and electricallycoupled to at least one of the remote and local wind measurement devicesfor supplying electrical power thereto.
 45. The meteorologicalmeasurement system according to claim 44, further comprising a batteryarrangement electrically connected to the solar cell arrangement forelectrical charging of the battery arrangement.
 45. The meteorologicalmeasurement system according to claim 34 further comprising a batteryarrangement carried by the mast and electrically connected to at leastone of the remote and local wind measurement devices for supplyingelectrical power thereto.
 47. The meteorological measurement systemaccording to claim 34, wherein the substrate is formed by the ground.48. The meteorological measurement system according to claim 47, whereinthe mast comprises a mast tiltably postionable with respect to theground.
 49. The meteorological measurement system according to claim 34,further comprising a plurality of retention cables secured between themast and the substrate.
 50. The meteorological measurement systemaccording to claim 34, wherein the remote measurement device furthercomprises a wave transmitter for transmitting a signal, wherein at leasta portion of the signal being scattered or reflected in the atmosphere.51. The meteorological measurement system according to claim 50, whereinthe remote measurement device further comprises a wave receiverreceiving at least a portion of the signal transmitted from the wavetransmitter.
 52. The meteorological measurement system according toclaim 51, wherein the signal transmitted from the wave transmitter iscollimated to form a plurality of beams which are transmitted indifferent directions inclined with respect to a vertical direction andwhich together define a geometry which tapers in the direction towardsthe mast.
 53. The meteorological measurement system according to claim52, further comprising an evaluation unit operably connected to theremote wind measurement device, and wherein measurement values obtainedfrom the signal received by the wave receiver and scattered or reflectedby means of remote measurement locations which are located on differentbeams and which have the same vertical spacing with respect to theremote wind measurement device are evaluated by the evaluation unit toform a horizontal wind speed and a vertical wind speed.
 54. Themeteorological measurement system according to claim 50, wherein thesignal is selected from the group consisting of a electromagneticsignal, an acoustic signal or combinations thereof.
 55. Themeteorological measurement system according to claim 50, wherein thesignal transmitted by the wave transmitter is scattered or reflected oninhomogeneities or particles present in the air.
 56. The meteorologicalmeasurement system according to claim 50, further comprising a secondmast extending in an upward direction from the substrate is spacedrelation to the mast, the second mast carrying a second wave receiverwhich is arranged in the region of the upper mast tip of the second mastand operable to receive at least a portion of the signal.
 57. Themeteorological measurement system according to claim 56, wherein thesecond mast carries a second remote wind measurement device includingthe second wave receiver and a second wave transmitter arranged in anupper mast tip region of the second mast, the second wave transmittertransmitting a second signal, wherein at least a portion of the secondsignal being scattered or reflected in the atmosphere.
 58. Themeteorological measurement system according to claim 57, wherein atleast a portion of the second signal is received by the second wavereceiver.
 59. The meteorological measurement system according to claim57, wherein the wave transmitter associated with the remote windmeasurement device and the second wave transmitter are operable totransmit signals at different frequencies such that the frequency of thesignal from the remote wind measurement device is different from thefrequency of the signal from the second transmitter.
 60. Themeteorological measurement system according to claim 57, wherein thesignals from the remote wind measurement device and from the second wavetransmitter are each transmitted in a temporally pulsed manner.
 61. Themeteorological measurement system according to claim 60, wherein thesignals from each transmitter comprise a wave pulse having asynchronization portion at a beginning thereof transmitted to the otherwave receiver for measuring the period of time until the arrival of therespective associated wave pulse.
 62. The meteorological measurementsystem according to claim 57, wherein the second remote wind measurementdevice is selected from the group consisting of a LIDAR system, a SODARsystem or combinations thereof.
 63. The meteorological measurementsystem according to claim 34 in combination with a wind turbinemechanism, wherein the mast is external with respect to the wind turbinemechanism.
 64. The meteorological measurement system according to claim34, further comprising a compensation device for detecting movement ofthe mast tip relative to the substrate and for compensating forinfluences of such movements on the wind properties measured by theremote wind measurement device.
 65. The meteorological measurementsystem according to claim 64, wherein the compensation device comprisesat least one movement measurement device which is arranged in the regionof the upper mast tip.
 66. A method for measuring the wind condition inan area with the at least one meteorological measurement systemaccording to claim 34 comprising: establishing a first set of windconditions in an area which is void of a wind turbine; and establishinga second set of wind conditions in the area which has at least one windturbine constructed therein, wherein the second set of wind conditionsare measured during construction or after completion of the at leastwind turbine.